Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Paramount => Topic started by: Horatio on August 27, 2014, 09:48:17 AM
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Hi, I have just ordered a Paramount Kit and would like to know if the EML 300b Mesh tubes work with the current stock kit. I feel like this question has probably been answered but reading through the forum I have not been able to find a current answer that gives me the confidence one way or the other.
Any help in this would be much appreciated - if they won't work I would certainly be open to alternative suggestions...
Many thanks,
Bill
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The owner of EML states that his tubes are guaranteed in the current soft start version of the Paramount amp. He also recommends running the mesh 300B at 22 Watts of dissipation but says that up to 28 Watts is OK. A 300B runs at about 26 Watts in a Paramount. I will note here that a Western Electric 300B was rated for a maximum dissipation of 36 Watts, so that 26W operating point is well within the safe margin for an original spec 300B.
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Excellent, thats great news - especially given the good things I have been reading about those tubes. Many thanks for the quick response!
Bill
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I run EML mesh plates in by custom Paramounts without a problem. They are within 4% as specified by EML.
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There was never a problem with 300Bs in the Paramount. There was an issue with a few specific 2A3 tubes (the circuitry is different). The "soft-start" board upgrade (incorporated into the kit with version 1.1, in 2011) was developed specifically to address an issue at startup, which was seen most severely by the EML and one or two other 2A3s.
The other issue is that EML specifies +/-4% for filament voltage, but power line voltages can vary +/-10% (sometimes more outside the US). Never fear, we have ways to adjust that voltage if necessary. You might check your power line before you start the actual assembly.
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Paul, checking my mains power with a basic Power / Energy Monitor my mains voltage (I am in the UK) is showing as fluctuating between 240 and 245 volts (most of the time it seems to hover around 243 although I am sure I saw a 239 at one point last night)... I have no idea how accurate the monitor itself is...
Bill